Re: [PATCH v2 1/9] dt-bindings: arm: Add support for DSB element

[Suzuki K Poulose]

On 27/02/2023 03:07, Tao Zhang wrote:
> Hi Suzuki,
>
> 在 2/22/2023 2:11 AM, Suzuki K Poulose 写道:
> > On 19/01/2023 07:41, Tao Zhang wrote:
> > > Add property "qcom,dsb-elem-size" to support DSB(Discrete Single
> > > Bit) element for TPDA. Specifies the DSB element size supported
> > > by each monitor connected to the aggregator on each port. Should
> > > be specified in pairs (port, dsb element size).
> > >
> > > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > > Signed-off-by: Tao Zhang <taozha@xxxxxxxxxxxxxxxx>
> > > ---
> > >   .../bindings/arm/qcom,coresight-tpda.yaml          | 22 
> > > ++++++++++++++++++++++
> > >   1 file changed, 22 insertions(+)
> > >
> > > diff --git 
> > > a/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml 
> > > b/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml
> > > index 2ec9b5b..298db7f 100644
> > > --- a/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml
> > > +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml
> > > @@ -58,6 +58,26 @@ properties:
> > >       minItems: 1
> > >       maxItems: 2
> > >   +  qcom,dsb-element-size:
> > > +    description: |
> > > +      Specifies the DSB(Discrete Single Bit) element size supported by
> > > +      each monitor connected to the aggregator on each port. Should be
> > > +      specified in pairs <port, dsb element size>.
> >
> > Isn't this a property of the TPDM connected to the port ? i.e. the DSB 
> > size ? Thus shouldn't this be part of the TPDM device (and the TPDA 
> > will be able to find it from the TPDM device) ?
> Since  the port number is about the input port of TPDA, this property 
> needs to be configured in the TPDA-related settings.

That is because, you chose to describe the property of TPDM in TPDA ?
Instead if you do it as follows :

 tpdm {
       qcom,tpdm-dsb-elemenet-size = <32>
       out_ports {

	port {
             remote-endpoint=<&tpda_port_number>;
	}
 }

 tpda {
       in_ports {
           port {
                 remote-endpoint=<&tpdm0_port0>;
           }
       }
 }


The TPDA driver can figure out the "port" that a given TPDM is connected
to and thus find out the DSB size. For the tpda driver, pdata->conns
could hold the reference to the TPDM device and thus fetch the DSB size.
(Note: James is working on a patch to add input port connections to the
platform data).

Suzuki